Stay bolt for steam boilers



Oct. 2 1923. 1,469,688

A. F. PITK!N v STAY BOLT FOR STEAM BOILERS I Filed Feb. e, 1925 F I G 2 4\%; $E5 I v I M E Patented Oct. 2, 1923.

warren sra'ras ARTHUR F. PITKIN, OF SCHENECTADY, NEW YORK.

STAY BOLT FOR STEAM BOILERS.

Application filed February 6, 1923. Serial No. 617,200.

T 0 all whom it may concern:

Be it known that I, ARTHUR F. PITKIN', a citizen of the United States, of Schenectady, in the county of Schenectady and State of New York, have invented a certain new and useful Improvement in Stay Bolts for Steam'Boilers, of which improvement the following is a specification.

My invention relates to-staybolts for connecting, and resisting outward pressure upon, the inner and outer sheets of steam boilers, of the general class or type set forth in Letters Patent of the United States'No. 1,432,085, granted and issued to me under date of October 17, 1922. The object of my present invention is to provide improved means for connectin the plug of the stay bolt structure to a boiler sheet.

The improvement claimediis hereinafter fully set forth.

In the accompanying drawing: Fig. 1 is a view, half in elevation, and half in axial section, of so much of a stay bolt structure as illustrates an embodiment of my invention; and, Fig. 2 an axial section showing a modification of structural detail.

I In the practice of my invention, referring descriptively to the specific embodiment thereof which is herein exemplified, the plug, 2, by which the stay bolt structure is connected to an outer sheet, A, of a firebox, instead of being made solid, as in prior practice, is recessed or relieved, either partially, as shown in Fig. 1, or entirely, as shown in Fig. 2, thereby bein .in the form of a shell or case, of annu ar transverse section throughout, and having a wall of such thickness as will safely sustain the strain to which it is exposed in service, while being sufficiently thin to be expanded by the application of .internal pressure by a proper tool.

The upper end portion of the plug may be of either frusto-con-ical or cylindrical form, and it is connected to the outer firebox sheet, A, by being fitted, in a hole of corresponding section, drilled in the sheet, and

sheet;- and welding material connecting the firmly secured therein by expanding its Wall, by a suitable expanding tool, so as to form a plurality of swells or projections, 2, on its periphery, which abut'against the inner or the outer sideof the sheet, A, or both. The projections which bear on the outer side of the sheet, are turned down thereon, and the plug may, if desired, be additionally secured by welding, the welding material 3, being applied around the projections on its outer end.

A tell tale hole, 2, in the neck,2 of the plug, and a ball, 2*, integral therewith, to which the body, 1, of the stay bolt, is articulated, are shown in Fig. 1, and Fig. 2 shows a separate ball, 2, around which the wall of the plug is pressed, the body of the stay bolt being articulated to the portion of the Wall which surrounds the ball.

I claim as my invention and desire to secure by Letters Patent:

1. In a stay bolt structure, the combination of a bolt, having a socketed head; and a sheet plug articulated. thereto, said plug having an annular wall, on which there is formed a plurality of peripheral swells or projections, adapted to bear against the sides of a boiler sheet.

2. In a stay bolt structure, the combination of a bolt, having a socketed head; a sheet plug, articulated thereto, said plug hav ing an annular wall, on which there is formed a plurality of'peripheral swells or projections, adapted to bear against a boiler outer end of said plugto a boiler sheet.

3. In a stay bolt structure, the combination of a bolt, having a socketed head; a ball; and a sheet plug having a wall enclosing said ball, and articulated to said bolt, and having a peripheral projection, adapted to bear against a boiler shee a ARTHUR F. PITKIN. Witnesses: CLARENCE B. BUxToN, THOMAS C. RAIN. 

